增加几个辅助列x,y,cnt

data a;
set a;
if wchg<=10 then x=0;
else x=1;
run;

data a;
set a;
by usubjid ;
y=lag(x);
if first.usubjid then cnt=0;
if x=y then do;
   retain cnt;
end;
else cnt+1;
run;

data a;
set a;
format want best12.;
by usubjid cnt;
if first.cnt then want=vsstresn;
retain want;
run;